Reservoir with oil level probe

Abstract

The invention proposes an oil reservoir for a turbine engine, provided with a probe (48) for measuring the oil level. The probe may be a capacitive electrical probe, inserted into the reservoir so as to be arcuate. A sleeve (66) encircles lamellar electrodes (60, 62) of the probe (48) to guide the probe (48) into the reservoir during mounting and to hold the electrodes in position. A method of mounting the probe (48) in a reservoir (30) is also disclosed.

Description

TANK WITH OIL LEVEL SENSOR

[0001] The invention relates to measuring the level of liquid, and in particular oil, in a turbomachine tank. The invention also relates to a turbomachine, in particular an aircraft turbojet or an aircraft turboprop. The invention further relates to a method for mounting a measuring probe in a tank. Prior art

[0002] In turbomachines, the liquid reservoirs and in particular the oil reservoirs generally have an arcuate shape, embracing the curvature of the turbomachine, in particular in order to limit the size of the turbomachine.

[0003] Measuring the oil level in a tank can involve different technologies, including capacitive or resistive probes, measuring variations in capacitance or electrical resistance in the tank and deducing the quantity of oil.

[0004] While a slightly curved tank can accommodate straight measuring probes, this is not the case for a tank with a small radius of curvature: straight probes inserted into a very curved tank would touch the inner wall of the tank. This would create an electrical contact that would disrupt the measurement. Also, a straight probe does not penetrate far enough to the bottom of the tank and is therefore unable to deliver values ​​when the level is particularly low.

[0005] Thus, it is known, in particular from document EP 3 399 164 B1, to provide an arcuate probe according to the general curvature of the tank. The probe is received in a sheath or in a plurality of supports which thus impose its arcuate shape on it. This design has certain limitations, in particular in terms of protection of the probe during its insertion into the tank, because the sheath or the supports can affect the space between the electrodes, or even damage the electrodes. Also, this design is unsuitable for single-piece tanks produced by additive manufacturing, because the supports or the sheath which are parts in contact with the probe cannot be metallic.

[0006] The invention aims to solve at least one of the problems posed by the prior art. More specifically, the invention aims to propose a lightweight design in which the mounting and dismounting of the oil level measuring probe are facilitated and in which it is ensured that even for significant tank curvatures, the measurement accuracy is not deteriorated.

[0007] The subject of the invention is an oil tank for a turbomachine comprising: a generally curved wall; an electrical probe for measuring the oil level, the probe having one or more arcuate lamellar electrode(s) following the curvature of the wall; and at least one sleeve, remarkable in that the sleeve is fitted onto the lamellar electrode(s) so as to be interposed between the electrode(s) and the wall, and in that the sleeve is fixed to the probe while being free of fixing with the wall.

[0008] Thus, the sleeve(s) prevent the electrodes from directly touching the tank, which is advantageous both to avoid any damage to the electrodes, to avoid their contact with metal parts and to ensure correct positioning of the electrodes.

[0009] According to an advantageous embodiment of the invention, the sleeve is oblong in shape having a longitudinal axis which is transverse to the lamellar electrode(s). Such an arrangement allows good compactness and the fact that the sleeve has a longitudinal direction perpendicular to the electrodes prevents twisting of the electrodes.

[0010] According to an advantageous embodiment of the invention, the sleeve comprises internal notches accommodating the lamellar electrode(s). It is thus possible to precisely position the lamellar electrodes in the tank. Measurement accuracy is thus guaranteed: in fact, if the electrodes move in the tank during the flight, their position no longer corresponds to their initial position (during calibration or calibration).

[0011] According to an advantageous embodiment of the invention, the notches are formed by protruding tabs in the shape of a “V”. Such a shape allows for easier placement of the strips in the sleeve because the strips are clamped in the notches and it is therefore easier to fix the strips to the sleeve. The elasticity of the tabs also contributes to maintaining the electrodes in position.

[0012] According to an advantageous embodiment of the invention, the sleeve comprises an internal through cavity occupied entirely by the lamellar electrode(s) and by a wedge. This not only allows the lamella to be held securely in position but also prevents oil from penetrating and becoming blocked in the sleeve.

[0013] According to an advantageous embodiment of the invention, the sleeve has a generally oblong shape with two opposite ends in the form of spheres. This shape facilitates the penetration of the probe with the sleeve into the tank and prevents the sleeve from damaging the walls of the tank. Also, the absence of a sharp edge on the sleeve prevents scratching the wall of the tank and generating particles which would spread in the oil.

[0014] According to an advantageous embodiment of the invention, the sleeve is fixed to the probe by means of a pin, a rivet, or a screw element, engaged in a hole of exactly one (or more) electrode(s). When there are several electrodes, fixing to a single electrode is sufficient and avoids over-stressing the electrodes. Alternatively, several fixing means can be provided to fix each electrode to the sleeve.

[0015] According to an advantageous embodiment of the invention, the tank comprises several sleeves and the wall has a non-constant curvature, the sleeves being irregularly distributed along the probe, the sleeves being further apart from each other the greater the curvature of the wall. This makes it possible to avoid areas of accumulation of bending stresses and therefore to smooth the bending stresses progressively on the probe. Consequently, damage to the probe is avoided and measurement accuracy is guaranteed. Alternatively, the curvature is constant and the sleeves are regularly spaced along the probe. The sleeves may be distributed over the majority or substantially the entire length of the probe.

[0016] According to an advantageous embodiment of the invention, the wall is a wall of an arcuate sheath, preferably formed of two U-shaped profiles facing each other and connected to each other by a lattice. Thus, the sleeve can come into contact with the U, with a slight assembly clearance. The lattice allows the oil to flow and thus prevents the accumulation of oil in the sleeve or in the sheath. Alternatively or in addition, the sheath can be that described in document EP 3 399 164 B1, that is to say be an articulated sheath. The sheath can extend over the majority or substantially the entire length of the probe. It can extend over the majority or substantially the entire length of the tank. Alternatively, the wall in contact with the sleeve is an internal wall of the tank.

[0017] According to an advantageous embodiment of the invention, the sleeve is made of electrically insulating material. This makes it possible to make the tank and in particular the wall in contact with the sleeve of metallic material, because there will be no electrical contact disturbing the electrodes which could impact the accuracy of the oil level measurement.

[0018] The invention also relates to a turbomachine equipped with such a tank. The turbomachine can be mounted on an aircraft capable of performing so-called “negative g” flight phases.

[0019] The invention also relates to a method for mounting an electrical oil level measuring probe in a curved turbomachine tank, the method comprising the following steps: (a) fixing one or more sleeve(s) to one or more lamellar electrodes of the probe; and (b) introducing the electrode(s) with the sleeve(s) into the tank.

[0020] According to an advantageous embodiment of the invention, at the fixing step, the electrode(s) is / are straight, and during introduction, the electrode(s) is / are progressively arched due to the contact of the sleeve(s) with a wall of the tank.

[0021] According to an advantageous embodiment of the invention, in the fixing step, the electrode(s) is / are arched according to a constant or non-constant curvature, and during the introduction step, the electrode(s) retains its / their curvature.

[0022] According to an advantageous embodiment of the invention, the reservoir comprises an opening, in particular an upper filling opening, and during the introduction step, the electrode(s) is / are introduced via said opening.

[0023] It is understood that each detail of an embodiment below may be combined with each other detail of the other embodiments.

[0024] The represents a turbomachine according to the invention;

[0025] Illustrates a reservoir according to the invention;

[0026] Lamontre a portion of the scabbard;

[0027] Laet sketches a capacitive probe and an associated sleeve;

[0028] Laet larepresent a resistive probe and an associated sleeve. Detailed description

[0029] It represents in a simplified way an axial turbomachine. In this specific case, it is a double-flow turbojet engine adapted to aircraft flight.

[0030] The turbojet 2 comprises a low-pressure compressor 4, a high-pressure compressor 6, a combustion chamber 8 and one or more levels of turbines 10. In operation, the mechanical power of the turbines 10 transmitted to the rotor 12 sets the two compressors 4 and 6 in motion. The rotation of the rotor around its axis of rotation 14 thus makes it possible to generate an air flow and to gradually compress the latter until it enters the combustion chamber 8.

[0031] An inlet fan commonly referred to as a fan or blower 16 is coupled to the rotor 12 and generates an air flow which is divided into a primary flow 18 passing through the compressors and a secondary flow 20. A reducer 22 can reduce the rotation speed of the blower 16 and / or the low pressure compressor 4 relative to the associated turbine level 10. The reducer 22, as well as transmission shafts 24 articulated by bearings 26, are lubricated by an oil circuit. Pumps 28 ensure the circulation of the oil in the circuit, from and to a reservoir 30.

[0032] The location of the tank 30 is here figurative. In reality it can be mounted on the fan casing, and more preferably inside the stator 32 separating the primary flow 18 from the secondary flow 20, which are respectively channeled by a primary vein and a secondary vein.

[0033] This is a sectional view of an oil reservoir 30 of a turbomachine such as that of the. The flows 18 and 20 are represented therein. The reservoir 30 may be housed between a compressor casing 36 and a partition 38 guiding the secondary flow 20.

[0034] The tank 30 is generally curved. Its general outline is arched to fit into the circular stator 32 of the turbomachine. Its outer wall 40, or casing, comprises a curved radially inner surface. The height of the tank may be at least 50 cm and it may describe an angular portion of at least 10°. The radius of curvature of the wall 40 may be between 30 cm and 2 m.

[0035] The tank 30 comprises a generally closed enclosure 42. The latter can store at least 30 liters of oil 44. The enclosure 42 is also curved. The top of the tank 30 has an opening 46 closed by a plug.

[0036] The tank can be metallic and / or can be manufactured by additive manufacturing of the ALM type. It can be single-piece and integrate the fixing brackets and various internal functional elements (baffle, deaerator, etc.).

[0037] In order to measure and / or estimate the volume of oil 44 in the tank, a measuring system can be introduced into the tank. This system can comprise an electrical probe 48 immersed in the liquid, and a computer transforming the measured electrical quantity into a value in liters. The probe 48 is arched, for example according to a radius of curvature, constant or not. It follows the curved shape of the tank. The probe 48 extends over the majority or the entire height of the enclosure 42. Thus, it can be in contact with the oil in substantially the entire useful volume of the enclosure 42.

[0038] The probe 48 may comprise one or more electrical electrodes coming into electrical contact with the oil. It may be capacitive, in which case it measures the capacitance between two lamellar and parallel electrodes. It may be resistive, in which case it measures the electrical resistance of its immediate environment.

[0039] The probe 48 may be immersed in the reservoir 30 or may be inserted into a sheath 50 of the reservoir. The sheath 50 may be metallic and / or manufactured by additive manufacturing together with the reservoir.

[0040] The sheath 50 may extend over substantially the entire height of the reservoir 30 and / or the entire length of the probe 48. The sheath 50 may be perforated to facilitate the entry and exit of the oil, in order to come into contact with the probe 48.

[0041] The curvature of each of the elements (tank 30, external wall 40, wall of the sheath 50 and probe 48) can be constant or variable. Thus, the notations R1 and R2 in the figure materialize the fact that the curvature can vary for these elements. Each of the elements can have its own curvature independent of the other elements, with the exception of the probe 48 which has a curvature imposed by the wall (wall 40 of the tank or wall of the sheath 50) with which it cooperates.

[0042] Lamontre shows an example of an embodiment of the sheath 50. In this example, the sheath 50 is made up of two U-shaped rails 52, 54, parallel to each other, facing each other, and connected to each other by a trellis 56.

[0043] The U's form indirect contact walls with the probe 48.

[0044] Lamontre a capacitive probe 48. This comprises two lamellar electrodes 60, 62. The electrodes 60, 62 are sufficiently flexible to be bent in flexion during, or before, their placement in the reservoir 30. The electrical capacitance between the electrodes 60, 62 reflects the quantity of liquid separating them and is therefore an image of the oil level in the reservoir. The two electrodes 60, 62 are fixed together by a connector 64 which can be attached to the reservoir at the opening (46 on the). The connector is also equipped with electrical connections for connecting the probe to a computer. The reservoir 30 can therefore comprise fixing elements (not shown) for the probe 48 at the opening 46 to immobilize the probe 48 despite the movements of the oil 44 and the vibrations.

[0045] At least one of the electrodes (here 60) is provided with orifices 61 allowing the attachment of one or more sleeve(s) 66.

[0046] The sleeve 66 encircles the two electrodes 60, 62 while keeping them at a distance from each other.

[0047] The sleeve may have two hemispherical ends 68, 70 which may be engaged in the grooves of the U-shaped rails ().

[0048] A fixing means 72 (pin, rivet, screw) can ensure the fixing of the sleeve 66 to the electrode 60.

[0049] A flat 74 may facilitate fixing or prevent the screw / rivet head from protruding from the sleeve 66. Alternatively, the screw / rivet head may be countersunk in the sleeve 66.

[0050] The sleeve 66 may be generally oblong or ovoid in shape, having a longitudinal axis 76 which extends transversely to the length of the electrodes 60, 62.

[0051] Illustrates the sleeve 66 alone. This is composed of an oblong body, that is to say a cylindrical body 78 with two hemispherical ends 68, 70. The body 78 is hollowed out to receive the electrodes 60, 62 in a through cavity 80.

[0052] The cavity 80 may be provided with notches 82 receiving the lamellar electrodes 60, 62. The notches 82 may be the result of tabs 84 projecting internally in the through cavity 80. The tabs 84 may have a “V” shape to facilitate the insertion of the electrodes 60, 62 and / or to give the tabs a certain elasticity allowing the electrodes 60, 62 to be held by wedging.

[0053] The tabs 84 may be substantially parallel to the flat 74.

[0054] The right-hand part of the diagram shows a section in the AA direction identified in the isometric view. In particular, it can be seen that an internal surface delimiting the cavity can also have a V-shape facing the tabs 84.

[0055] The angle of the V noted α can be between 150 and 170°.

[0056] Lamontre a resistive probe. In this example, the probe 48 comprises a single lamellar electrode 60 provided with resistors 63 distributed along the electrode. The resistors 63 have a common terminal and a free terminal, the circuit being therefore open. The liquid closes the circuit and the liquid level influences the equivalent resistance which is measured.

[0057] The sleeve 66 may be identical to that used for the capacitive probe of the previous figures. Alternatively, and as drawn in Figures 6 and 7, the sleeve 66 may comprise a single notch and a corner 90 filling the through cavity 80.

[0058] The wedge 90 may have a shape substantially complementary to the cavity 80. Means of fixing by screw and nut, pin, rivet, etc. may be provided to keep the wedge 90 fixed to the body of the sleeve 66 and thus wedge the electrode 60.

[0059] Whether in the case of a capacitive electrode (figures 4 and 5) or resistive electrode (figures 6 and 7), several sleeves 66 can be arranged along the electrodes. For example, when the radius of curvature is small, the sleeves will be closer to each other, in order to smooth the deformation of the electrodes and avoid areas of concentration of bending stresses.

[0060] It is understood that a probe may be provided with more than two electrodes, and in particular, the capacitive and resistive electrodes may be combined, one or more sleeves encircling all the electrodes. Also, other probes may be attached to the same sleeve(s), such as for example a temperature probe.

[0061] Finally, a wedge 90 can be arranged in the example of figures 4 and 5, for example to fill a space left free in the middle of the cavity between the electrodes 60, 62.

[0062] The invention also relates to a method of mounting the probe 48. The sleeve(s) 66 are first fixed to one or more lamellar electrodes 60, 62. Then, the assembly is introduced into the reservoir, for example through an opening (type opening 46).

[0063] Upon insertion, the electrodes 60, 62 are forced – by the contact of the sleeve and the wall 40 or the rails 52, 54 – to bend.

[0064] Alternatively, the electrodes 60, 62 may be arched before their introduction (with the sleeves 66 attached) into the reservoir 30.

[0065] In addition to the advantages mentioned above, the sleeve 66 makes it possible to electrically isolate the electrodes from the tank. A series of sleeves 66 makes it possible to guarantee a constant distance between the electrodes 60, 62, over their entire length. Also, the rounded shapes of the sleeve 66 prevent stagnation or blockage of the liquid which can easily flow around or inside the sleeve 66 and the electrodes 60, 62.

[0066] It should be noted that the invention is presented in relation to an oil tank for a turbomachine, but those skilled in the art will understand that the invention also relates to any other liquid and any other type of tank (for example, water, fuel, liquid hydrogen, etc.).

Claims

Oil reservoir (30) for a turbomachine (2) comprising:- a generally curved wall (40, 52, 54);- a probe (48) for electrically measuring the oil level (44), the probe (48) having one or more arcuate lamellar electrode(s) (60, 62) following the curvature of the wall (40, 52, 54); and- at least one sleeve (66), characterized in that the sleeve (66) is fitted onto the lamellar electrode(s) (60, 62) so as to be interposed between the electrode(s) (60, 62) and the wall (40, 52, 54), and in that the sleeve (66) is fixed to the probe (48) while being free of fixing with the wall (40, 52, 54). Tank (30) according to claim 1, characterized in that the sleeve (66) is oblong in shape having a longitudinal axis (76) which is transverse to the lamellar electrode(s) (60, 62). Tank (30) according to one of the preceding claims, characterized in that the sleeve (66) comprises internal notches (82) receiving the lamellar electrode(s) (60, 62). Tank (30) according to the preceding claim, characterized in that the notches (82) are formed by protruding tabs (84) in the shape of a “V”. Tank (30) according to one of the preceding claims, characterized in that the sleeve (66) comprises an internal through cavity (80) occupied entirely by the lamellar electrode(s) (60, 62) and by a corner (90). Tank (30) according to one of the preceding claims, characterized in that the sleeve (66) has a generally oblong shape with two opposite ends in portions of spheres (68, 70). Tank (30) according to one of the preceding claims, characterized in that the sleeve (66) is fixed to the probe (48) by means of a pin (72), a rivet (72), or a screw element (72), engaged in a hole (61) of exactly one (of the) electrode(s) (60). Tank (30) according to one of the preceding claims, characterized in that it comprises several sleeves (66) and in that the wall (40, 52, 54) has a non-constant curvature (R1, R2), the sleeves (66) being irregularly distributed along the probe (48), the sleeves (66) being further apart from each other the greater the curvature (R1, R2) of the wall (40, 50). Tank (30) according to one of the preceding claims, characterized in that the wall (52, 54) is a wall of an arcuate sheath (50), preferably formed of two U-shaped profiles (52, 54) facing each other and connected to each other by a lattice (56). Tank (30) according to claim 1, characterized in that the sleeve (66) is made of electrically insulating material. Turbomachine (2) for aircraft comprising an oil reservoir (30) of generally curved shape, characterized in that the reservoir (30) conforms to one of the preceding claims. Method for mounting a probe (48) for electrically measuring the oil level in a curved tank (30) of a turbomachine (2), the method comprising the following steps: fixing one or more sleeve(s) (66) to one or more lamellar electrodes (60, 62) of the probe (48); and introducing the electrode(s) (60, 62) with the sleeve(s) (66) into the tank (30). Method according to claim 12, characterized in that in the fixing step, the electrode(s) (60, 62) is / are straight, and during introduction, the electrode(s) (60, 62) is / are progressively arched due to the contact of the sleeve(s) (66) with a wall (40, 52, 54) of the reservoir (30). Method according to claim 12, characterized in that in the fixing step, the electrode(s) (60, 62) is / are arched according to a constant or non-constant curvature (R1, R2), and during the introduction step, the electrode(s) (60, 62) retain(s) its / their curvature (R1, R2). Method according to one of claims 12 to 14, characterized in that the reservoir (30) comprises an opening (46), in particular an upper filling opening, and during the introduction step, the electrode(s) (60, 62) is / are introduced via said opening (46).

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